Is it permissible to purchase a house in Europe with an interest-based loan due to the absence of Islamic banks, bearing in mind the Prophet's (peace be upon him) hadith about neighbors?

There is no harm in purchasing a house through a permissible means, and we recommend it if possible. However, it is not permissible to buy it through usurious banks except in cases of dire necessity (ḍarūrah), and there is no such necessity in what you have mentioned. You have done well by considering the rights of the neighbor, acting upon the recommendation of the Prophet, peace and blessings be upon him: "Whoever believes in Allah and the Last Day, let him honor his neighbor."